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Publication numberUS4903413 A
Publication typeGrant
Application numberUS 07/011,102
Publication dateFeb 27, 1990
Filing dateFeb 5, 1987
Priority dateFeb 7, 1986
Fee statusLapsed
Also published asDE3703493A1
Publication number011102, 07011102, US 4903413 A, US 4903413A, US-A-4903413, US4903413 A, US4903413A
InventorsPhilip R. Bellwood
Original AssigneeRank Taylor Hobson Limited
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Surface profile measurement of workpieces
US 4903413 A
Abstract
In order to measure the surface profile of a workpiece, a yoke having two fixed feet is held in contact with the surface as the workpiece is rotated. A dynamic probe is mounted on the yoke by means of a transducer which outputs a signal dependent upon the position of the dynamic probe relative to a transducer datum. The fixed feet and the foot of the dynamic probe have a similar shape and size so that they detect irregularities in the workpiece surface with equal sensitivity. Fourier analysis of the signal caused by movement of the dynamic probe directly by the workpiece and also by movement of the yoke enables the profile of the workpiece to be determined. In order to improve the frequency response of the transducer output over the range of harmonics considered, the angles between the dynamic probe and the fixed probes are unequal. The apparatus does not require a precision spindle type machine to rotate the workpiece and is therefore particularly suitable for in situ measurement of workpiece profiles.
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Claims(14)
I claim:
1. An apparatus for measuring a surface profile of a workpiece having a generally circular section, comprising a probe assembly, means for rotating the workpiece relative to the probe assembly, the probe assembly comprising a yoke, a pair of feet mounted on the yoke for engagement with the workpiece surface at the section to be measured at first and second locations spaced in the direction of relative movement so that the feet and yoke follow variations in the surface profile upon such movement, and detector means which is mounted on the yoke operable to provide a signal dependent upon the distance relative to the probe assembly of a third location on the work piece surface spaced from the feet locations in the direction of relative movement, the signal varying in accordance with the relative rotational position of the workpiece and the probe assembly, the feet being adapted to follow variations in the surface profile substantially as closely as the detector means, the apparatus further comprising signal processing means responsive to the signal from the detector means for determining the surface profile of the workpiece, said signal processing means being operable to take into account variations in the detected distance due to movement of the yoke caused by the feet engaging irregularities in the surface profile in addition to variations in the detected distance due to surface irregularities directly detected by the detector means.
2. An apparatus as claimed in claim 1, characterized in that the feet are adapted to make essentially point contact with the workpiece.
3. An apparatus as claimed in claim 1, characterized in that the feet are each fixed rigidly to the yoke.
4. An apparatus as claimed in claim 1, characterized in that the relative spacings of the first and second locations and the second and third locations are not equal.
5. An apparatus as claimed in claim 4, characterised in that the relative spacings are in the ratio of an even number to one.
6. An apparatus as claimed in claim 5, characterised in that the relative spacings are in the ratio of 4:1.
7. An apparatus as claimed in claim 1, characterized by a further detector means for providing a signal dependent upon the distance relative to the probe assembly of a fourth location on the workpiece surface spaced from the first, second and third locations in the direction of relative movement of the workpiece and the probe assembly.
8. An apparatus as claimed in claim 7, characterized in that the relative spacings of the second and third locations and the first and third locations are not equal and in that the relative spacings of the first and fourth locations is equal to the relative spacing of the second and third locations.
9. An apparatus as claimed in claim 7, characterized in that the relative spacing of the first and fourth locations is not equal to the relative spacing of the second and third locations.
10. An apparatus as claimed in claim 7, further comprising means for adding the signals of the two detector means.
11. An apparatus as claimed in claim 1, and including a second such probe assembly spaced from and connected to the first mentioned probe assembly and further detector means mounted with respect to the first and second probe assemblies for providing a signal dependent upon the distance to a further location on the workpiece spaced from the planes of detection of the detector means of the first and second probe assemblies.
12. An apparatus as claimed in claim 1, characterized in that the feet are adapted to make essentially line contact with the workpiece along a line transverse to the direction of relative movement.
13. Apparatus as claimed in claim 1 wherein said signal processing means includes means for deriving from said detector signal amplitudes and phases associated with each harmonic of a Fourier series representing the surface profile of the workpiece as a plurality of harmonics.
14. Apparatus as claimed in claim 13, wherein said means for deriving said amplitudes and phases of said Fourier series representing the surface profile includes means for determining amplitudes and phases of another Fourier series representing said detector signal as a plurality of harmonics, each harmonic in said detector signal Fourier series having a first amplitude and phase attributable to movement of the third location relative to the probe assembly, in combination with second and third amplitudes and phases attributable to the movement of the probe assembly at the first location and the second location, respectively, the second and third amplitudes having predetermined ratios with respect to the first amplitude, and the second and third phases having predetermined offsets from the first phase.
Description
FIELD OF THE INVENTION

This invention relates to an apparatus and method of measuring a surface profile of a workpiece.

In particular, a first aspect of the present invention is concerned with an apparatus for measuring a surface profile of a workpiece, comprising a probe assembly having a pair of feet and a detector means, the probe assembly being movable relative to the workpiece such that the feet engage the workpiece surface at first and second locations spaced in the direction of relative movement, the detector means being operable to provide a signal dependent upon the distance relative to the probe assembly of a third location on the workpiece surface spaced from the feet locations in the direction of relative movement.

BACKGROUND TO THE INVENTION

A V-block measuring apparatus is known in which a workpiece is rotated relative to a V-block having flat sides contacting an external surface of the workpiece at the first and second locations, for example as shown in U.S. patent specification 3274693. This specification also shows in FIGS. 9 and 10 thereof, an apparatus acting in the same way as the V-block apparatus, but for measuring internal surfaces, and having rounded feet for engaging the workpiece at the first and second surfaces.

A disadvantage of the V-block apparatus and of the internally-measuring modification thereto is that the sides of the "V" or the feet follow coarse irregularities in the surface, but not fine irregularities, and therefore the signal from the detector means does not completely represent the surface profile.

SUMMARY OF THE INVENTION

The first aspect of the present invention is characterised in that the feet are adapted to follow variations in the surface profile substantially as closely as the detector means. Alternatively, given a desired sensitivity to surface variations, not only the detector means but also the feet are arranged to produce that sensitivity.

Thus, the apparatus provides a signal which can be processed (as described below) to determine the profile taking into account movement of the probe assembly due to irregularities in the workpiece profile. Indeed, the apparatus may include means responsive to the signal to determine the surface profile of the workpiece, the determining means being operable to take into account variations in the detected distance due to movement of the probe assembly caused by the feet engaging irregularities in the surface profile in addition to variations in the detected distance due to surface irregularities directly in line with the detector means.

Preferably, the feet are adapted to make essentially point contact with the workpiece or line contact with the workpiece along a line transverse to the direction of relative movement. For example, the feet may be "hatchet" or "toroidal" feet, in order to follow the workpiece surface closely.

Fourier analysis may be employed to determine the amplitudes and phases of a plurality of harmonics by which the workpiece profile can be represented. In the case where the detecting means and feet are asymmetrically disposed, it has been found that a flatter amplitude frequency response can be achieved, especially at the ends of the range of harmonics considered. Preferably, the relative spacings of the first and third locations and of the second and third locations are in the ratio of an even number to one, for example 4:1, in order to provide a flatter amplitude frequency response at the middle of the harmonic range.

The apparatus may also include a further detector means for providing a signal dependent upon the distance relative to the probe assembly of a fourth location on the workpiece surface spaced from the first, second and third locations. The signals of the two detector means may be added, and the probe assembly may be arranged so that the relative spacing of the first and fourth locations is equal to the relative spacing of the second and third locations. This then has the effect of eliminating phase distortion of the frequency response. Alternatively, the probe assembly may be arranged so that the relative spacing of the first and fourth locations is not equal to the relative spacing of the second and third locations. This then has the effect of extending the frequency response to interleaving the two component frequency responses across the harmonic range.

The apparatus may include a second such probe assembly spaced from the first mentioned probe assembly and further detector means mounted with respect to the first and second probe assemblies for providing a signal dependent upon the distance to a further location on the workpiece spaced from the planes of detection of the detector means of the first and second probe assemblies. The apparatus can then be used to measure roundness, eccentricity, cylindricity and taper of a generally cylindrical workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a view of a surface profile measuring apparatus:

FIGS. 2 to 4 are diagrams to illustrate movements of parts of the apparatus of FIG. 1;

FIG. 5 is an amplitude frequency response graph for the apparatus;

FIG. 6 is a schematic drawing of another apparatus; and

FIG. 7 is an exploded perspective view of a further apparatus.

DESCRIPTION OF THE EMBODIMENT

Many present methods of measuring complete profiles of workpieces necessitate removing the workpiece from the workshop to either an instrument for surface measurement of the precision spindle type or a computer controlled coordinate measuring machine. Whilst the apparatus described below can be used with a precision spindle instrument, it may also be used in a machining workshop, without the need for removing the workpiece from the machine, because the apparatus does not rely upon the axis of rotation of the workpiece being accurately set with respect to the measuring apparatus. It is, however, necessary to provide on the machine which rotates the workpiece some means for angular datum detection, such as an optical sensor cooperating with an apertured disc mounted for rotation with the workpiece.

Referring to FIG. 1, a generally cylindrical workpiece 10 to be measured is mounted for constant speed rotation about an apparatus axis 0, the nominal axis 0' of the workpiece being approximately co-axial with the apparatus axis 0. A probe yoke 12 carries two relatively fixed probes 14, 16 and also one dynamic probe 18 mounted for radial movement in conjunction with a transducer stator 20 which outputs a signal S linearly related to the position of the dynamic probe 18 relative to the yoke 12. Each of the probes 14, 16, 18 has a hatchet or toroidal foot 22, 24, 26 for engaging the workpiece 10. The feet are of similar shape and size. The yoke 12 is pivotally attached to one end of an arm 28, the other end of which is pivotally attached to the apparatus, so that the yoke can move generally vertically as seen in FIG. 1 and also rock about its pivotal connection to the arm 28 to allow the feet 22, 24 of the fixed probes 14, 16 to ride on the surface of the workpiece as it rotates. The dynamic probe is spring-loaded to maintain its foot 26 in contact with the workpiece 10.

The motion of the apparatus shown in FIG. 1 will now be described with reference to FIGS. 2 to 5, in which the positions of the probe feet 22, 24, 26 are designated C, A, B respectively, and a transducer stator datum is denoted D. A yoke centre Y is defined on the line of action BY of the dynamic probe and at a distance Ro from the point of contact of each foot A, C. The feet B, C and B, A are angularly spaced by angles α and β about the yoke centre Y.

FIG. 2 shows the case where the workpiece causes an increment of radius RA at foot A, so that it moves to position A' without the radial position of the foot B moving. This movement causes an increment of radius RDA of the transducer datum D from the original yoke centre Y. From the geometry of FIG. 2, it can be determined that:

RDA =RA sin α/sin (α+β)

Since the foot B does not move from the reference surface, a transducer signal SA due to the movement RDA between the foot B and transducer datum D caused by movement of the foot A is:

SA =-kRA sin α/sin (α+β)

where k is a transducer constant relating output signal to displacement.

Similarly, referring to FIG. 3, an increment of radius RC at the foot C causes an increment of radius RDC of the transducer datum from the original yoke centre Y, such that:

RDC =RC sin β/sin (α+β)

This produces a transducer signal SC such that:

SC =-kRC sin β/sin (α+β)

Referring to FIG. 4, an increment of radius RB at the foot B does not cause any movement of the yoke and transducer stator datum D and thus a signal SB is produced such that:

SB =kRB 

The immediately preceding description describes the case where the workpiece is static and increments of radius are produced at the three feet A, B, C. Consider now that the workpiece is rotated and it will be noted that: ##EQU1## where θ is the angle of a datum radial line L on the workpiece with respect to the radial line passing through the foot B.

It follows, therefore, that the signals attributable to the movements of the feet A, B, C are ##EQU2##

In the following description, the terms a and b are adopted such that: ##EQU3##

The total signal is:

S=SA +SB +SC =k{R(θ)-bR(θ+β)-aR(θ-α)}

The radius profile of a section of a workpiece can be expressed as a Fourier series:

R(θ)=ΣCn cos [nθ+νn ]

where n are integers which are the harmonic numbers; νn is the phase of the nth harmonic; and Cn is the amplitude of the nth harmonic. It will be noted, therefore, that: ##EQU4##

Substituting into the equation for the signal S:

S=kΣCn {cos [nθ+νn ]-b cos [n(θ+β)+νn ]-a cos [n(θ-α)+νn ]}

Since the values k, a and b are known, it is possible, using standard Fast Fourier Transform (FFT) techniques and a computer, to obtain the values of Cn and νn over a desired range of harmonics from the variation of the signal S during one rotation of the workpiece at a constant speed. Once these values are known, they can be substituted back into the equation:

R(θ)=ΣCn cos [nθ+νn ]

Thus, the radius profile is determined.

The Fourier series representing the signal S can be written as:

S=kΣAn Cn cos [(nθ+νn)+φn ]

where: ##EQU5##

An represents the amplitude frequency response of the nth harmonic and φn represents the phase shift frequency response.

In the case where α=β, the amplitude frequency response is 1-(cos (nβ)/cos β) and has values of zero for n=1 and n=(2π/β)-1. The maximum value of the amplitude frequency response occurs for the value n=π/β. A pass-band thus occurs between the values of n=2 and n=(2π/β)-2 centred on n=π/β.

In the case where α=β=π/10 (18°), the amplitude frequency response is as shown by the dashed line in FIG. 5. It will be noted that the amplitude frequency response for n=2 and n=18 is about one-tenth of that for n=10, which is undesirable, since a flatter frequency response would produce less likelihood of error.

By adopting an asymmetric probe arrangement, that is with α and β being unequal, it is possible to improve the performance of the apparatus.

Multiplying out the square of the amplitude frequency response:

An 2 =1+a2 +b2 -2a cos (nα)-2b cos (nβ)+2ab cos [n(α+β)]

For α>β and thus a<b, this square can be considered to be of the form of a steady curve 1+a2 +b2 -2b cos (nβ) modified by a ripple component of -2a cos (nα)+2ab cos [n(α+β)]. With increasing α, the ripple component effects a rapid increase of response with respect to n in the neighbourhood of the pass-band limits, thus producing a flatter response.

Preferably, the ripple component should detract from the steady component at mid-band (nmid =π/β), so as to improve further the flatness of the response, rather than produce a pronounced peak. By setting α=2mπ/nmid, where m is an integer, the ripple component -2a cos (nα)+2ab cos [n(α+β)] becomes -(2a+2ab), which is a negative minimum. For the arrangement of FIG. 5, possible values of α to produce this result are 2π/10, 4π/10 and 6π/10. In FIG. 5, the dotted line shows the amplitude frequency response for the values β=π/10 and α=4π/10 It will be seen that the response has maxima of about 2.1 at n=8 and n=12, and that the response at n=2 and n=18 is about 3/10 of the response at n=8 or n=12.

In a modification of the arrangement described above, the yoke 12 is fitted with a further transducer 20' and dynamic probe 18', as shown schematically in FIG. 6 of the drawings, set at an angle α from the probe 14. In one arrangement, the angles β and α are set equal and the output signals of the transducers 20, 20' are simply summed in the case where the transducers have equal transducer constants k. If the increments of radius of the workpiece profile are considered to be the sum of two components of each harmonic, one being the sine component and the other being the cosine component relative to the direction of symmetry of the yoke 12, then the cosine components add due to even symmetry, but the sine components subtract and cancel due to odd symmetry. Therefore, the resultant frequency response has no phase error. In an alternative arrangement, the angles β and α are set unequal. Thus, the ripple components of the frequency responses of the two probes 18, 18' will be interleaved and thus yield an extended frequency response.

Whilst the embodiments described above are suitable for measuring roundness of a generally cylindrical workpiece in one radial plane, reference is now made to FIG. 7 which illustrates a modified apparatus for measuring roundness, eccentricity, cylindricity and taper of a generally cylindrical workpiece.

The apparatus includes a pair of yoke assemblies 30, 32 generally similar to that shown in FIG. 1, but connected by a rigid spacer member 34. The spacer member is connected by a ball and cone bearing 36 to one end of an arm 38 enabling pivoting about all axes, and the other end of the arm is pivotally connected to a support member 40 for axial pivoting. Each yoke assembly 30, 32 has a pair of fixed feet 42, 44, 46, 48 and carries a respective transducer 50, 52. It will be appreciated that each yoke assembly 30, 32 acts independently in a similar manner to the arrangement of FIG. 1, and thus R50 (θ) and R52 (θ) in the radial planes of the transducers 50, 52 can be determined. However, further transducers 54, 56 are also mounted on the spacer member in different radial planes. Therefore, having determined R50 (θ) and R52 (θ), from R50 (θ) and R52 (θ) and the signals produced by the transducers 54, 56 it is possible also to determine R54 (θ) and R56 (θ) in the radial planes of each of the further transducers 54, 56 and thus deterine the roundness, eccentricity, cylindricity and taper of the workpiece.

It will be appreciated that further modifications and developments may be made to the apparatus described above. For example, the probe foot 18 and transducer 20 could be replaced by an optical or ultrasonic measuring device. The apparatus is not limited to measuring generally round section workpieces and may be modified for measuring, for example, linearity and flatness.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3056209 *Jan 4, 1960Oct 2, 1962Aeronautical Engineering Res IMethod and apparatus for measuring surface contours
US3274693 *Feb 4, 1965Sep 27, 1966Bendix CorpMethod and apparatus for roundness measurement
US3942253 *May 3, 1974Mar 9, 1976Iosif Davydovich GebelDevice for measuring deviation of the normal section profile of a part from the round shape
DE1944605A1 *Sep 3, 1969May 27, 1971Perthen Johannes Dr IngVorrichtung zur Messung der Rundheit von zylindrischen Werkstuecken
DE2912640A1 *Mar 30, 1979Sep 4, 1980Bbc Brown Boveri & CieMessgeraet zur kruemmungsmessung
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5077908 *Jun 25, 1990Jan 7, 1992David MooreApparatus for measuring the roundness of a surface of an object
US5337485 *Sep 21, 1992Aug 16, 1994Chien An YRoundness error and crown electronic measuring system
US5551906 *Nov 23, 1994Sep 3, 1996Voith Sulzer Paper Technology North America Inc.Caliper assembly for grinder
US6229297 *Jun 30, 1999May 8, 2001Hewlett-Packard CompanyDevice for determining the position of an object relative to a surface
US6247241 *Feb 4, 1999Jun 19, 2001Nsk Ltd.Ball diameter automatic measurement device and method
US6327788 *Dec 6, 1996Dec 11, 2001Taylor Hobson LimitedSurface form measurement
US6519861 *May 4, 2000Feb 18, 2003Raytheon CompanyMechanical centering apparatus and method
US6564466 *Sep 26, 2001May 20, 2003Fuji Jukogyo Kabushiki KaishaMeasuring apparatus for pulley
US6690991 *Apr 3, 2000Feb 10, 2004Tokyo Seimitsu Co., Ltd.Machine control gage system performing roundness measuring function
US6820347 *Apr 3, 2003Nov 23, 2004Harford Industries, Inc.Electronic micrometer for sensing the diameter of a cylindrical body
US6871416 *Aug 19, 2002Mar 29, 2005Canyon Street Crossing, LlcEccentricity and wobble sensing device
US7036238 *Dec 21, 2004May 2, 2006Mitutoyo CorporationWidth-measuring method and surface texture measuring instrument
US7047658 *Jan 19, 2001May 23, 2006Marposs Societa Per AzioniApparatus and method to measure the dimensional and form deviation of crankpins at the place of grinding
US7107696 *Oct 18, 2004Sep 19, 2006Harford Industries, Inc.Electric micrometer for sensing the diameter of a cylindrical body
US7159477 *Mar 13, 2002Jan 9, 2007Borealis Technology OyApparatus for inspecting deformation of pipes
US7461462 *Feb 28, 2006Dec 9, 2008Aktiebolaget SkfDevice, method, computer program product, and carrier for indicating at least one of an orbit of, and a deviation from a nominally round surface
US7472490Mar 2, 2006Jan 6, 2009Hcc/Kpm LlcShape-measuring assembly for a grinding machine
US7589824 *May 22, 2007Sep 15, 2009Sure-Shot Medical Device, Inc.Surface curvature measurement tool
US7607239Jun 7, 2001Oct 27, 2009Marposs, Societá per AzioniApparatus for checking diametral dimensions of cylindrical parts rotating with an orbital motion
US7909676 *Jul 26, 2006Mar 22, 2011Techint Compagnia Tecnica Internazionale S.P.A.Independent measuring apparatus for grinding machines
US7954253Sep 15, 2009Jun 7, 2011Marposs Societa' Per AzioniApparatus for checking diametral dimensions of a rotating cylindrical part during a grinding thereof
US8286361Apr 28, 2011Oct 16, 2012Marposs Societa' Per AzioniApparatus for checking diametral dimensions of a cylindrical part in orbital motion in a numerical control grinding machine
US8336224Sep 20, 2010Dec 25, 2012Hommel-Etamic GmbhMeasuring device
US8429829Mar 28, 2011Apr 30, 2013Hommel-Etamic GmbhMeasuring device
US8534194 *Sep 28, 2007Sep 17, 2013Bobst Bielefeld GmbhRotary printing press and method for adjusting a cylinder thereof
US8667700Sep 7, 2012Mar 11, 2014Marposs Societa' Per AzioniMethod for checking the diameter of a cylindrical part in orbital motion
US8725446Jul 8, 2010May 13, 2014Hommel-Etamic GmbhMethod for determining the shape of a workpiece
US9393663Aug 22, 2011Jul 19, 2016Hommel-Etamic GmbhMeasuring device
US9562756Sep 20, 2013Feb 7, 2017Jenoptik Industrial Metrology Germany GmbhMeasuring device with calibration
US20020020075 *Jun 7, 2001Feb 21, 2002Dall'aglio CarloApparatus for checking diametral dimensions of cylindrical parts rotating with an orbital motion
US20030038724 *Aug 19, 2002Feb 27, 2003Leja Joseph W.Eccentricity and wobble sensing device
US20030056386 *Jan 19, 2001Mar 27, 2003Franco DanielliApparatus and method to measure the dimensional and form deviation of crankpins at the place of grinding
US20030177850 *Dec 11, 2002Sep 25, 2003The Washington Post CompanySystem and method for verifying the roll roundness of rolls of paper used for newspapers
US20030188446 *Apr 3, 2003Oct 9, 2003Harford Industries, Inc.Electronic micrometer for sensing the diameter of a cylindrical body
US20050050746 *Oct 18, 2004Mar 10, 2005Harford Industries, Inc.Electric micrometer for sensing the diameter of a cylindrical body
US20050120812 *Mar 13, 2002Jun 9, 2005Emil EdwinApparatus for inspecting deformation of pipes
US20050132591 *Dec 21, 2004Jun 23, 2005Mitutoyo CorporationWidth-measuring method and surface texture measuring instrument
US20060196065 *Feb 28, 2006Sep 7, 2006Aktiebolaget SkfDevice, method, computer program product, and carrier for indicating at least one of an orbit of, and a deviation from a nominally round surface
US20080163509 *Mar 2, 2006Jul 10, 2008Hcc/Kpm LlcShape-Measuring Assembly for a Grinding Machine
US20080289205 *May 22, 2007Nov 27, 2008Thierman Jonathan SSurface curvature measurement tool
US20080299872 *Jul 26, 2006Dec 4, 2008Techint Compagnia Tecnica Interazionale S.P.A.Independent Measuring Apparatus for Grinding Machines
US20100000109 *Sep 15, 2009Jan 7, 2010Dall Aglio CarloApparatus for checking diametral dimensions of a rotating cylindrical part during a grinding thereof
US20100018419 *Sep 28, 2007Jan 28, 2010Fischer & Krecke Gmbh & Co. KgRotary Printing Press and Method for Adjusting a Cylinder Thereof
US20100248594 *Feb 18, 2010Sep 30, 2010Darrel NishSetup tool for grinder sharpening jigs
US20110232117 *Mar 28, 2011Sep 29, 2011Hommel-Etamic GmbhMeasuring device
US20150285609 *Apr 1, 2015Oct 8, 2015Jtekt CorporationMachine tool including affected layer detection sensor
CN104655080A *Feb 25, 2015May 27, 2015大连理工大学High-precision radial adjustable involute master of gear and adjusting method
Classifications
U.S. Classification33/551, 33/555.1
International ClassificationG01B5/207, G01B7/28, G01B21/20, G01B21/30
Cooperative ClassificationG01B7/282, G01B5/207
European ClassificationG01B7/28C, G01B5/207
Legal Events
DateCodeEventDescription
Mar 5, 1987ASAssignment
Owner name: RANK TAYLOR HOBSON LIMITED, 2 NEW STAR ROAD LEICES
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BELLWOOD, PHILIP R.;REEL/FRAME:004700/0247
Effective date: 19870222
Owner name: RANK TAYLOR HOBSON LIMITED, (A BRITISH CORP.),UNIT
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BELLWOOD, PHILIP R.;REEL/FRAME:004700/0247
Effective date: 19870222
Aug 26, 1993FPAYFee payment
Year of fee payment: 4
May 12, 1997ASAssignment
Owner name: TAYLOR HOBSON LIMITED, ENGLAND
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:RANK NEMO (HTR) LIMITED, (PREVIOUSLY KNOWN AS RANK TAYLORHOBSON, LTD. AND RANK TAYLOR HOBSON LIMITED);REEL/FRAME:008535/0246
Effective date: 19970411
Aug 25, 1997FPAYFee payment
Year of fee payment: 8
Sep 18, 2001REMIMaintenance fee reminder mailed
Feb 27, 2002LAPSLapse for failure to pay maintenance fees
Apr 23, 2002FPExpired due to failure to pay maintenance fee
Effective date: 20020227